Identification of a highly virulent Fusarium commune strain as a new soybean root rot pathogen in Indiana

Authors: DETRANALTES, CHRISTOPHER - Purdue University; SALDANHA, MEGHNA - Purdue University; Scofield, Steven - Steve; Cai, Guohong

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Characterizing the distribution of emergent pathogens is critical for developing local disease management strategies. Diseased soybean (Glycine max (L.) Merr.) seedlings were sampled as part of a bulk collection of seedling pathogens from Purdue’s ACRE research station in the summer growing season of 2020. One isolate of Fusarium commune K. Skovg., O'Donnell & Nirenberg was recovered from a seedling showing necrotic lesions of the cotyledons and hypocotyl as well as dark necrotic rot of the tap and lateral roots. A single-spore isolate was obtained and grown on potato dextrose agar as well as synthetic low-nutrient agar amended with sterile filter paper. The isolate (AC101) produced colonies and spores that matched the morphological description of F. commune. ITS, mtSSU and TEF1a sequences matched 100% to accessions of F. commune deposited in GenBank including one isolate from the original species description. Koch’s postulates were completed by planting healthy soybean seeds (cv. Williams) in inoculated or mock-inoculated sand-cornmeal mixtures and growing the plants for two weeks in a greenhouse. All seedlings in the inoculated replicates showed symptoms similar to the field symptoms of the original host but with more severe damage. Control plants remained healthy. F. commune was successfully recovered from inoculated plants but not control plants. This is the first report of Fusarium commune infecting soybean in the state of Indiana. Attempts should be made to assess disease risk in this newly reported geographic region.